Three-level phase shifted ZVS-PWM DC-DC converter with neutral point diodes clamping and flying capacitor

This paper presents some experimental results and practical evaluations of neutral point clamping and flying capacitor hybrid three-level phase shifted soft switching PWM DC-DC high power converter with high frequency transformer and center-tapped rectifier. This new DC-DC converter developed for TIG, MIG and MAG arc welders is implemented by modifying the high-frequency-linked HB soft switching PWM DC-DC power converter with high side and low side two active edge resonant modular, which is proposed by the authors. The operating principle of the three-level soft-switching PWM DC-DC converter and its experimental and simulation results including phase-shifted angle vs. power regulation characteristics and power conversion efficiency characteristics in addition to power loss analysis are illustrated and discussed from a practical point of view, along with the remarkable advantageous points as compared with previously-developed soft switching PWM DC-DC converter. Finally, the improved three-level soft switching PWM converter version is also considered to suppress the circulating current due to phase shift pulse modulation principle. The PWM and PDM dual pulse modulation strategy is considered to extend its soft switching transition operation range.